The present invention relates to a transparent LED display device, and more particularly, to device capable of viewing an external foreground of a rear surface on a front surface of a transparent image plate and an external foreground of the front surface of a transparent image plate on the rear surface of the transparent image plate while viewing a high-brightness image or an autostereoscopic image in a transparent structure such as a transparent window by a viewer.
Generally, a clear image condition is possible when the brightness of an image itself is twice more than the ambient brightness.
An image device which views the image by a transparent plate structure by deleting a rear backlight structure of an LCD or an OLED is known. However, since such an image needs to use ambient light, it is impossible to view the image in a dark place and the brightness itself is dark even though the image device has a self light emitting function.
That is, transmittance is as low as 5 to 15%, so transparency is lowered, and the brightness is usually as low as 200 to 300 cd/m2 even though a backlight is used.
On the other hand, the ambient light of an exhibition place or a business place where such an image device is installed is usually about 1,000 lux (330 cd/m2), so that the image is relatively dark.
In addition, an LED display device as a light emitting diode emits red, green, and yellow light when current flows in a semiconductor made of Ga (gallium), P (phosphorus), and AS (arsenic) and the brightness reaches a maximum of 1,000 cd/m2 or more when the LED display device is used as an image pixel.
Such a light emitting diode module may be configured in a structure in which a light emitting area is large, while a thickness is small.
In the case of the structure of a modular electric signboard in Korean Patent Application No. 10-2014-013077, a technique that can view an exterior through a gap of the LED modules spaced apart from each other inside is known.
In the case of a spectacle 3D LED structure in Korean Patent Application No. 10-2014-0071281, a plurality of LEDs are arranged in line and neighboring strip substrates are arranged with an image separation distance so as to see background behind the image separation distances.
However, the display device structure is used as a light source in the related art, but in order to simultaneously observe the rear background as shown in FIG. 14(a), an image separation distances D1 between LED plates D1 is at least 1:2 to 1:20, the image is not properly formed, the image is rough, and when the LED plate D1 is not in use, the LED plate D1 itself has become a hindrance to practical use due to the refusal such as obscuring the field of view.